Self-propelled projectile



C,G.ABB0T. SELF PHOPELLED PROJECTILE.

APPLICATION FILED JAN. Il, 1919.

Patented May 31, 1921.

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A TTUHIVEY UNITED STATES PATENT OFFICE.

CHARLES G. ABBOT, 0F WASHINGTON, DISTRICT 0F COLUMBIA.

SEM-PROPEIILED PROJECTILE.

Speccation of Letters Patent. Patented May 31, 1921.

Application led January 11,* 1919. VSerial No. 270,687.

To ali 'whom it may concern.'

Be it known that I, CHARLES G. lArmor, a citizen of the United States of America, residing at Washington, in the Distrlct` of Columbia, have invented certain new and useful Improvements in Self-Propelled Projeclsmooth-bore guns, and which has a chamber containing a propelling medium, such as powder, with bores or passages tangent to the walls of the chamber and extending to the rear of the projectile in such a manner that when the propellant within the chamber is ignited the rush of gases through these passages propels the projectile forwardly, and at the same time causes the rotation of the projectile while inthe gun, thus utilizing the full effect of the gases.

A further object of my invention is to provide a selfpropelled projectile of the type mentioned 1n whichmeans is provided for preventing a circulatory movement of the gases within the chamber which contains the propellant, j thus, increasing the reactive force of the gases.

A further object of my invention is to provide a projectile containing therein a propellant, the walls of the projectile itself aiding in resistingthe bursting effect oithe charge, and thereby permitting the use of the projectile in smooth-bore guns of relatively light weight, since the ypropelling force, .in addition to being resisted by the walls of the projectile, is applied gra l and not suddenly, as inthe case of the ordinary projectile, which is discharged by propellants contained entirely within the gun..

Other objects and advantages will appear in the following specification, and the novel features of the invention will be particularlypointed out in the appended claims.

My invention is illustratedin the accompanying drawings, forming part of this ap- 'plicatiom in which;

Flgure 1 1s a sectional view through one form of the projectile and through a portion of a smooth-bore gun; v

Fig. 2 is a rear view ofthe projectile;

dually Fig. 3-is a view partly in section, of the projectile as used in a trench mortar;

Fig. 4 is a side view of a modied form of the device, the vrear part being shown in section;

Fig. 5 is a rear view shown in Fig. 4; and F Figf is a'section along the line 6-6 of A number of attempts to produce the rotation of projectiles for use with smoothbore guns, have been made. stance, as far as I am aware, these lattempts have failed where such projectiles have been used as ordnance, due to the. fact that the projectiles have been constructed so that the of the projectile In -each inrotative force could be applied while the l projectile is in'flight. In certain instances, attempts have been made to obtain the rotative eect by air resistance. 'Y In other devices, the kinetic energy of the ldischargin gases has been used to produce a turbine eigfect. In such devices it Ohas been necessary to construct spiral grooves and the difficulties of proportioninor these grooves, as well as the cost of manul'acturing projectiles of .this type, have rendered these devices im.- practical.

The present' invention relates to a projectile for use with smooth-bore guns in which the full force of the propellant contained within the projectile is utilized in propelling 'the projectile forwardly and in rotating it while within the gun. eferring now to the drawings, 1 indicates the gun which is provided with a smooth bore 2 and, in the present instance, withj'a priming passage 3.

In Fig. 1, the projectile illustrated is a shell 4,. having a chamber 5 for the `bursting charge, and a chamber 6 for the propellant. Any suitable means may be. used for i niting thel bursting charge. At 7 I have lndicased an igniting device which ma' be a time'fuse, a centrifugally operated lgniter, or any other suitable ignition *means The chamber 6 is closed by means of a screwplug 8, which fits in a threaded opening 9, at the rear of the projectile. This screw plug may contain any suitable means for igniting the propellant within thechamber 6, as for instance, a percussion cap 10, which may` communicate by means (not shown) with thev propellant.

Extending rearwardly from the chamber 6 are passages l1. '.These, passages are arranged tangentially to the walls of the chamber 6, z'. e., they are tangent to a circle whose center is in the axis of the shell. The

passages 7 are preferably enlarged at their,

- gases within the chamber, 6 which would tend to reduce the eifectiveness of the pro'- pelling force were such circulation permitted.

From the foregoing description ofthe various parts of the device, the operation thereof may be readily understood. The projectile with its charge of propellant 13 is placed in the smooth-bore gun. When the propellant is ignited as, for instance, by means of apriming chargeA introduced through the priming passage 3, the gases passing rearwardly through the bores 11 generate a pressure which drives the projectile forwardly and at the same time the projectile is rotated on its axis while within the gun. The charge of propellant is proportioned so that its force is expended before the projectile leaves the gun, the pressure tending to drive the projectile forwardly is developed gradually and during this development of the pressure the walls of the projectile itself tend to'resist lateral forces. For these reasons a projectile of 'this type, i. e., a self-propelled projectile, may be used in a smooth-bore 'gun of much lighter weight than when the propelling charge is disposed entirely outside o f the projectile. This is an important advantage,

especially as fars the slow development of the propelling force is concerned. It will be noted that vthere are "no passages which extend to the front of the projectile or to the sides thereof. .All of the force which propels the projectile forwardly is from the rear.- In this respect the present invention differs from others which contain no propellant in the projectile itself. In the present instance use is made of all of the force generated.

the bores 11 be conical shaped or enlargedtoward their rear ends. I have found, by experiment, that unless baffles are used withinthe vchamber to provide resistance elements, the maximum propelling and rotating force cannot be attained.

In F igs. 4 to 6 inclusive, I have shown a modified form of the device in which the Vprojectile 4 is provided with'a chamber 6',

having baiiles 12', which are disposed longtudinally with respect to the axis of the projectile instead of transversely. In this form of the device, that is to say, in the form disclosed in Figs. 4f, 5 and 6, I have made use of additional bores 11. `Any suitable number, however, may be used. In this instance, the plug 8 is not provided' with an igniting means, the bores 11 being designedv to furnish means for igniting the' propellant within the chamber 6. f

My improved projectile is -.especially adapted for use with trench .mortars In Fig. 3, I have illustrated-a trench mortar15 into which a projectile 16 has been dropped.

The propellant within the projectile is de signed to be actuated by the striking of the cap 10 against lthe interior bottom of the mortar. The projectile is discharged and is rotated to insure true flight in the manner already described.

I claim: i

1. A self-propelled projectile, having a chamber, a propellant disposed within the chamber, the body portion of the projectile and being tangent to the walls of the chamber, and means within the chamber for pre- I venting circulatory currents therein.

3. A self-propelled projectile, having a chamber, the body portion of the projectile being provided with a plurality of coneshaped bores extending from the chamber to the rear end of the projectile, said bores being tangent to the walls of the chamber, and a plurality of baflies within the chamber for preventing circulatpry currents therein.

In testimony whereo afiix my Y CHARLES G, AB OT.

si ature.- 

